Mangrove zooplankton of North Queensland, Australia

Abstract

Egg production rates by the dominant copepod species in five rivers inNortheastern Australia were measured. An undescribed Oithona speciesproduced 2.3–15.3 eggs female⁻¹ d⁻¹,Oithona aruensis 0.8–11.3 eggs female⁻¹ d⁻¹, Parvocalanus crassirostris 1.3–36.2 eggsfemale⁻¹ d⁻¹, and Bestiolina similis3.6–51.4 eggs female⁻¹ d⁻¹. Oithona spp.appear to feed carnivorously, whereas the calanoid species B. similis andP. crassirostris were suspension feeders. Acartia sinjiensis fedopportunistically as a carnivore or as a suspension feeder. Grazing ratesdirectly measured in feeding experiments or calculated from egg productionrates were low (usually less than 31% of copepod body C per day),despite mangrove waters having apparently high food concentrations. Wesuggest that in spite of high standing stocks of potential foods, copepodswere in fact food-limited much of the time, and that the deficit betweenmetabolic costs and measured ingestion were met by intake of detritus by B.similis, P. crassirostris and Pseudodiaptomus griggae, and carnivory onlarger prey items by A. sinjiensis and Oithona spp. Turbulence andcannibalism may play important roles in the nutrition of mangrove copepods.Both phytoplankton-based and detritus-based food chains appear important inmangrove pelagic secondary production.